A HISTORICAL NOTE ON SCIENCE AND METAPHYSICS

The term ‘speculative metaphysics’ and the term ‘speculations,’ when used as synonyms for ‘metaphysics’ (by Boscovitch, Faraday, and others), indicate the view that metaphysical doctrines are products of the imagina­tion, in contrast with scientific theories which are - allegedly - products of inductive inference from facts.

Bacon’s violent opposition to metaphysics was less violent than the ultra-modern one. His opposition to metaphysics was merely an opposi­tion to its method; it was not an opposition to the abstract character of metaphysics but to the leaping to metaphysical conclusions. By devel­oping science properly, by starting with observation and then slowly de­veloping theories by gradually increasing the abstractness of knowledge, by ascending the inductive ladder properly without skipping any step, Bacon held, we shall end up with the most fundamental theory, namely, with scientific metaphysics. This metaphysics will be scientific because it will have been achieved, not by the speculative method, but by the in­ductive method.

Scientific metaphysics was later defended by Descartes and by Kant, each of whom considered his own metaphysics to be a body of certain, and hence scientific, knowledge. Their idea of certitude differed from Bacon’s; it was based on a priori reasoning rather than on inductive infer­ence. Consequently they viewed metaphysics as the beginning, not the end, of scientific inquiry. Buth both in viewing science as certain, and in taking it for granted that metaphysics must be scientific or perish, they barely differed from Bacon. It was William Whewell, the disciple of both Bacon and Kant, who first defended unscientific metaphysics from a scientific point of view.

In Whewell’s view scientific doctrines do not emerge inductively from facts; they are first imagined and then verified empirically. And he con­sidered his own (Newtonian-Kantian) metaphysics a priori valid, namely, demonstrable independently of empirical evidence. In accepting Kant’s apriorism he rejected Bacon’s view that all preconceived ideas are veri­fiable by virtue of their being prejudices, contending that much as people had sought to verify Newton’s optics, much as they were prejudiced in its favor, they ultimately rejected it. His problem was how to explain why assent to Newton’s mechanics was justifiable and assent to Newton’s optics unjustifiable. He wished to find out the proper canon of verification and show that Newton’s theory of gravity, but not Newton’s optics, had conformed to it.

In brief (and in a slightly improved version), Whewell’s canon can be put thus: proper verification is the result of severe tests. The procedure of severe testing is this: First try to explain known facts and state your explanatory theory as explicitly as possible. Then try to deduce in a rig­orous manner from the theory a new prediction of observable facts. Then, and only then, decide by observation whether this prediction is true or false. If the prediction is false then the theory is obviously false too; if the prediction is true then the theory obviously explains the new facts without adjustment (‘adjustment’ being a suitable alteration or addition).

Both Bacon and Whewell were interested in the problem of the de­marcation of science. But their interests stemmed from different roots. Bacon considered Aristotelianism, which was then the academic meta­physics, to be the chief impediment to the advancement of learning. Whewell viewed Newton’s metaphysics, which was by then the academic metaphysics, as demonstrable. His problem was not metaphysics but the overthrow of the allegedly verified Newtonian optics. Thus, while Bacon demarcated science mainly from metaphysics, Whewell demarcated science mainly from pseudo-science.

Since, according to Whewell, science begins by the invention of ex­planatory hypotheses, he was all for every possible source of inspiration. And he viewed all (reasonable) metaphysics as such a possible source. He gave a striking example for this. Kepler had developed his scientific hypo­theses, Whewell maintained, in an attempt to carry out Plato’s meta­physical program as outlined in his Timeus. This idea of Whewell’s was so revolutionary that this great philosopher is now almost entirely for­gotten because Mill and his followers condemned him as an intuitionist. (This charge is, of course, quite untrue. Whewell relied not only on in­tuition but also on Kantian transcendental arguments and on empirical tests.)

Initially, Popper’s interest in the problem of demarcation was similar to Whewell’s, though his examples were different; it was Marxism and Freudianism which he viewed as pseudo-scientific. His demarcation of science may be contrasted with Whewell’s thus: Whewell demands that a scientific theory be testable and emerge triumphant from the tests, while Popper merely demands testability. Neither of them is hostile to meta­physics, and both contend that metaphysics is sometimes important as a source of scientific inspiration. A remnant of positivist prejudice may perhaps be detected in Popper’s lumping together (like Bacon and unlike Whewell) of a few kinds of nonscientific theories, including metaphysics, pseudo-science, and superstition, under the one label ‘metaphysical.’ Though I dislike this label, I do not think it matters beyond leaving some ambiguity concerning the difference between metaphysics and pseudo­science.

IV.